Friday, July 22, 2011

Pioneer Anomaly Has A "Dull" Explantion

The quartet’s painstaking analysis of telemetry data suggests that
the anomalous acceleration of both spacecraft is decreasing with time.
While the exact nature of this decrease is not certain, there is a good
chance that it is exponential. This would be consistent with the decay
of radioactive material with a half-life of about 27 years. Both
spacecraft have radioactive power sources that are still running – so
mystery solved.

Well, not quite. Both spacecraft are powered by plutonium-238, which
has a half-life of about 88 years. However, the team believes that the
more rapid drop in acceleration could be the result of degradation and
changes to the thermal properties of the spacecraft over time. When
these factors are considered, claim the researchers, a half-life of 27
years seems reasonable.

This sounds like a tedious, painstaking task. So bravo to them for the monumental effort.